Also, a word of caution with aluminized foils.
Aluminum is a high reflectivity material. However it is a good heat conductor.
So it should be used where high radiation transfers are a concern, but it SHOULD NOT be used alone.
As a good practice, a layer of ceramic blanket or several thick coats of BVM heat shield should be placed under the aluminum foil as a conduction and convection barrier.
Also, beware of the type of glue used on the foil. It has to sustain high temperatures. In some cases, zirconia glue is required.
Finally is important to place the reflective element first in the transfer path, then the insulating coats.